This invention relates to the field of kinetic energy projectiles in general, and to improved long rod penetrators therefor. In particular, this invention relates to the difficult problem of lubricating a penetrator rod so it will remain lubricated throughout use, to enhance penetration into the target (armor).
Since the fourteenth century it has been known that lubricants can improve the armor penetration capability of arrows, shot and shell. In the Middle Ages this was done by capping arrowheads with bees wax; in our own time by polytetrafloride ethylene coating small arms bullets and tipping medium caliber armor piercing shot with zirconium, aluminum, and magnesium. In each case, the velocity required to penetrate a given target is reduced.
The application of lubricants to shot with higher length to diameter ratios, L/D, so that the lubricants remain thereon for effectiveness is more problematic for two reasons. Firstly, when a long rod penetrates a very thick single plate the exterior surface of the shot plays little or no part in the actual penetration zone. This is because the penetration takes place by erosion of the front surface, hydrodynamic penetration, and the shot surface flows backward never making contact with the armor. Secondly, when a long rod penetrates a multilayer array of steel plates any externally applied lubricant will be wiped off by the first plate.